<?php
    // +----------------------------------------------------------------------
    // | ThinkPHP [ WE CAN DO IT JUST THINK IT ]
    // +----------------------------------------------------------------------
    // | Copyright (c) 2006-2012 http://thinkphp.cn All rights reserved.
    // +----------------------------------------------------------------------
    // | Licensed ( http://www.apache.org/licenses/LICENSE-2.0 )
    // +----------------------------------------------------------------------
    // | Author: liu21st <liu21st@gmail.com>
    // +----------------------------------------------------------------------
    namespace think\db\connector;

    use PDO;
    use think\db\Connection;

    /**
     * Sqlsrv数据库驱动
     */
    class Sqlsrv extends Connection {
        // PDO连接参数
        protected $params  = [
            PDO::ATTR_CASE              => PDO::CASE_NATURAL,
            PDO::ATTR_ERRMODE           => PDO::ERRMODE_EXCEPTION,
            PDO::ATTR_STRINGIFY_FETCHES => false,
        ];
        protected $builder = '\\think\\db\\builder\\Sqlsrv';

        /**
         * 取得数据表的字段信息
         * @access public
         * @param string $tableName
         * @return array
         */
        public function getFields($tableName) {
            $this->initConnect(false);
            list($tableName) = explode(' ', $tableName);
            $sql = "SELECT   column_name,   data_type,   column_default,   is_nullable
        FROM    information_schema.tables AS t
        JOIN    information_schema.columns AS c
        ON  t.table_catalog = c.table_catalog
        AND t.table_schema  = c.table_schema
        AND t.table_name    = c.table_name
        WHERE   t.table_name = '$tableName'";
            // 调试开始
            $this->debug(true);
            $pdo = $this->linkID->query($sql);
            // 调试结束
            $this->debug(false, $sql);
            $result = $pdo->fetchAll(PDO::FETCH_ASSOC);
            $info   = [];
            if ($result) {
                foreach ($result as $key => $val) {
                    $val                       = array_change_key_case($val);
                    $info[$val['column_name']] = [
                        'name'    => $val['column_name'],
                        'type'    => $val['data_type'],
                        'notnull' => (bool)('' === $val['is_nullable']),
                        // not null is empty, null is yes
                        'default' => $val['column_default'],
                        'primary' => false,
                        'autoinc' => false,
                    ];
                }
            }
            $sql = "SELECT column_name FROM information_schema.key_column_usage WHERE table_name='$tableName'";
            // 调试开始
            $this->debug(true);
            $pdo = $this->linkID->query($sql);
            // 调试结束
            $this->debug(false, $sql);
            $result = $pdo->fetch(PDO::FETCH_ASSOC);
            if ($result) {
                $info[$result['column_name']]['primary'] = true;
            }
            return $this->fieldCase($info);
        }

        /**
         * 取得数据表的字段信息
         * @access public
         * @param string $dbName
         * @return array
         */
        public function getTables($dbName = '') {
            $this->initConnect(false);
            $sql = "SELECT TABLE_NAME
            FROM INFORMATION_SCHEMA.TABLES
            WHERE TABLE_TYPE = 'BASE TABLE'
            ";
            // 调试开始
            $this->debug(true);
            $pdo = $this->linkID->query($sql);
            // 调试结束
            $this->debug(false, $sql);
            $result = $pdo->fetchAll(PDO::FETCH_ASSOC);
            $info   = [];
            foreach ($result as $key => $val) {
                $info[$key] = current($val);
            }
            return $info;
        }

        /**
         * 解析pdo连接的dsn信息
         * @access protected
         * @param array $config 连接信息
         * @return string
         */
        protected function parseDsn($config) {
            $dsn = 'sqlsrv:Database=' . $config['database'] . ';Server=' . $config['hostname'];
            if (!empty($config['hostport'])) {
                $dsn .= ',' . $config['hostport'];
            }
            return $dsn;
        }

        /**
         * SQL性能分析
         * @access protected
         * @param string $sql
         * @return array
         */
        protected function getExplain($sql) {
            return [];
        }
    }
